Avastin does not help advanced breast cancer patients live longer, and it carries some significant drug side-effects, including a risk of death, the Food & Drug Administration (FDA) said today. The results of the FDA Avastin review make it less likely that the drug will be approved to treat breast cancer. An FDA advisory committee is to meet on Wednesday to discuss whether the FDA should give Genentech, the maker of Avastin, the OK to market the drug as a breast cancer treatment.
Avastin was approved by the FDA in 2004 to treat colon cancer, and in 2006, the agency approved it as a treatment for non-small cell lung cancer. Avastin was the first approved therapy designed to inhibit angiogenesis, the process by which new blood vessels develop and carry vital nutrients to a tumor. Avastin has been a blockbuster for Genentech, and its parent company Roche AG. For the first nine months of 2007, US sales of Avastin topped $1 billion.
FDA staff posted documents today from the agency’s review of Avastin in advance of Wednesday’s advisory committee meeting. The documents note that while Avastin did extend the period prior to patients’ breast cancer becoming worse, treatment with the drug did not markedly increase survival time. Generally, breast cancer patients treated with Avastin added to the chemotherapy drug paclitaxal lived only a month or two longer than those who where treated with paclitaxal alone.
The FDA documents also pointed out that Avastin caused serious side effects, including cardiovascular problems, bowel perforations, and a few deaths. About 71 percent of the women treated with Avastin and paclitaxal experienced a significant side effect, compared with 51 percent who were treated with paclitaxal alone. The FDA said that those side effects included 5 patient deaths that were “probably or definitely” due to Avastin. There were no deaths among patients receiving only paclitaxal. The FDA staff recommended that the benefits of Avastin in treating cancer be weighed against these side effects.
Many analysts expect that the FDA advisory panel will still approve Avastin for breast cancer treatment. Many of those on the panel will be physicians – and some will be oncologists – who might look favorably on having another tool in their limited arsenal against advanced breast cancer. As one doctor told the New York Times, “At the end of the day, oncologists are very familiar with the incremental improvements required to move cancer treatment forward.” But Wednesday’s FDA advisory panel meeting is sure to be contentious, and the outcome is not certain.
A controversial approval was not expected when Genentech first asked the FDA to OK Avastin as a breast cancer treatment. Prior to Genentech’s application, a clinical trial had found that Avastin added to paclitaxal doubled the amount of time it took for advanced breast cancer to worsen – a period known as “progression free survival”. Many doctors already use Avastin for this purpose, and the FDA’s approval would only mean that Genentech could market the drug as a breast cancer treatment. But Genetech’s application for Avastin as a breast cancer treatment has been stalled since September 2006, with the FDA questioning whether increased progression free survival was enough to justify the expanded use of Avastin. Generally, the agency prefers to see improvements in overall survival before it will expand the approved uses of a drug.